O-hydroxyaryl dihalotkiazines



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Patented Oct. 5, 1954 UNITED STATES o-HYDROXYARYL DIHALOTRIAZINESWendell P. Munro, Martinsville,

'William B.

Hardy, Bound Brook, and Asa W. Joyce, Plainfield, N. 3., assignors toAmerican Cyanamid Company, New York, N. Y., a corporation Maine NoDrawing. Application April 10. 1953, Serial No. 348,112

(Cl. 26il248) 9 Claims.

This invention relates to the production of2-:hydroxyaryl-4,6-dihalotriazines.

-A number of 2 .aryl --4,6'-'- dianthraquinonylaminotriazines have beenprepared and are valuable vat dyes. The best process for preparing thesevat dyes is condensation of aminoanthraquinones With2-aryl-4,6-dihalotriazines, a class of intermediate materials to whichthe compounds of the present invention belong. Recently an efiicientprocess has been developed for producing some of the2-aryl-4,6-dihalotriazines, which process involves four steps. In thefirst step an aroyl chloride is reacted with dicyandiamide to produce anaroyl dicyandiamide. This is hydrolyzed to the corresponding aroylbiuret, ring closed by means of alkali to form a2-aryl-4,6-dihydroxytriazine (also known as an aroyl guanamide), whichcan then be transformed into the correspondingZ-aryl-4,6-dichlorotriazine by means of phosphorus pentachloride. Thisdichloro compound is condensed with aminoanthraquinones to form thefinished dyestuff. These reactions, in the order listed, are describedin U. S. Patents 2,407,161, Kaiser and Thurston to American CyanamidCompany; 2,401,599, Adams to American C'yanamid Company; Ostrogovitch,Gazz. Chim. Ital, 62, 229 (1935) and 1,897,428, Hentrich et al., toGeneral Aniline Works. They may be represented by the followingformulas:

The above reactions, which are quite general, fail in the particularcase where R is o-hydroxyaryl. When it is attempted to prepare suchcompounds, side reactions occur and the triazine ring It has thereforebeen impossible in the past to produce 2-o-hydroxyaryl-4,6-dihalotriazines.

According to the present invention, it has been found that the abovecompounds can be produced by preparing2-o-alkoxyaryl-4,6-dihalotriaaines by the regular methods including theefficient processes described above. These compounds have the followinggeneral formula in which All; is a lower ,alkyl group, .i. e., .onehaving less than 6 carbon atoms, and X is halogen.

The alkoxy group, of course, is in the ortho position withrespect to thecarbon atom attached'to the triazine ring. Accordingito'the presentinvention, it has been found possible'to dealkylatethe alkoxy compoundsby reaction With a hydrogen halide having a molecular-weight greaterthanl2 such as hydrogen chloride,bromide, or iodide.

The splitting off of the alkyl group'may'be carried out under a widevariety of reaction conditions. It is an advantage of the presentinvention that the process is in no Way critical. In general, it isdesirable to effect dealkylation in a reaction medium containing anorganic solvent, the hydrogen halide vapors-being passed therethrough atelevatedtemperature-with thorough stirring. The organic-solventsmay be:aromatic or aliphatic and are preferablyhot too volatile so as 'toeliminate. the necessity of expensive pressure equipment. Typicalorganic solvents are chlorobenzene, the xylenes, 'o-di'chlorobenzene,nitrobenzene, propylene dichloride, .tetrahydro naphthalene,l-chloronaphthalene, tetrachloroethylene, and the like.

The temperature may vary widely although economically useful reactionrates are normally not obtainable materially :below C. From -200" C.excellent results are obtained although at the higher temperatures thesolubility of the hydrogen halide in the organic solvent decreases andtemperatures more nearly .in'the middle of the range are ordinarilypreferred in practical operation. 200 C. is about as high a temperatureas can be used because excessive temperatures also'tend to produce somedecomposition of the starting material or final product.

The reaction by which the alkoxy compound-is transformed into thehydroxy compound is moderately slow. The length of .time, .of course,will vary with batch. size, stirring efficiency, temperature, and otherfactors as is normal in batch operations. It is, however, not excessiveand-even large batches take no more than a few'hours. The outputofequipment is thereforesatisfactorily high.

Isolation of thefinal product presents no. problem as-side reactions aresubstantially absent and the product is obtained in 'high yield and goodpurity. This israther surprising as the triazine ring which issensitiveto acidic reagents appears to be unusually stable in'thedealkylation reaction. It is not known'why the o-alkoxyaryl compoundsshow the unique property of smooth .dealkylation with hydrogen .halidesaudit is .not intended .to limit the. invention to.any theory of thisanomalous behavior of the .oalkoxy group.

.The alkoxy compounds maybeprepared from a largenumber of .o-alkoxyaroylchlorides. Thus, .for example, the chlorides of such acids as o-anisicacid, o-ethoxybenzoic.acid,.2+methoxy-3- naphthoic acid,-o-propoxybenzoic acid, .4:chloro- 2-methoxybenzoic acid,5-bromo-2-propoxybenzoic acid, 4-methyl-2-methoxybenzoic acid, 5- nitrol-methyl-Z-methoxybenzoic acid, l-methoxy-2-naphthoic acid, 4 nitro 1methoxy 2 naphthoic acid, l-methoxyphenanthrene-2-carboxylic acid(Duvall and Mosettig, J. A. C. S. 60, 2409 (1938)3-methoxyphenanthrene-2-carboxylic acid (Gilman and Cook, J. A. C. S.62, 2813 (1940) or the like may be employed.

During dealkylation, halogen interchange fre- 1 quently occurs in thereactive halogens in the triazine ring; for example, if the startingmaterial is 2-(o-methoxyphenyl) -4,6-dichlorotriazine and is treatedwith hydrogen bromide, it may be found that the product is theZ-(o-hydroxyphenyl)-4,6-dibromotriazine. This is of small practicalconsequence, since the different dihalotriazines are of comparablereactivity, and may be used interchangeably in subsequent reactions, asindicated below.

The compounds of the present invention are valuable intermediates as thevat dyestufis obtained by condensing them with various anthraquinonylamines are materially brighter than compounds in which there is nosubstitution of hydroxyl in the 2-aryl group. They show a considerablehypsochromic shift, for example, the hydroxy group transforms areddish-yellow dye into a much cleaner and greener yellow. The dyestuffsproduced from the intermediates of the present invention also showimproved fastness to light and washing. We do not claim here thedyestuifs obtained by condensing the compounds of the present inventionwith anthraquinonyl amino compounds, these forming the subject matter ofthe copending application or" Gadea and Munro, serial No. 227,942 filedMay 23, 1951, now abandoned.

The invention will be described in greater detail in the followingspecific examples, the parts being by Weight unless otherwise specified.As some of the intermediate compounds are new. examples of theirpreparation are included, as well as examples for the production of thearyl dichlorotriazines, and some finished dyestuffs derivable therefrom.

EXAMPLE 1 o-Methozcybenzoyldicyandiamide A slurry of 120 parts ofacetone and 21 parts of dicyandiamide is cooled to 510 C. and treatedwith 26.4 parts of potassium hydroxide. After stirring at 0-5 C. untilthe reaction is substantially complete, the mixture is cooled below 0 C.and there is slowly added to it a solution of 34.1 partso-methoxybenzoyl chloride in 120 parts of acetone. Stirring is thencontinued until the reaction mixture comes to room temperature. It isdiluted to approximately the volume of 1000 Darts of water, and slowlyacidified with approximately 14 parts of .acetic acid. The resultingproduct is stirred thoroughly, filtered, washed, and air dried. It meltsapproximately at 186 C.

EXAMPLE 2 o-Methozcybenzoylbiuret A mixture of 80 parts ofo-methoxybenzoyldicyandiamide, prepared as described in Example 1, 400parts of Water, and 67 parts of a concentrated hydrochloric acid isgradually heated to reflux with stirring, and refluxed until biuretformation is complete. The slurry is then cooled to 0-5 C. and filtered.The product is washed with very dilute hydrochloric acid and air dried.It melts approximately at l94--196 C.

EXAMPLE 4 z-o-methoryphenyl dichlorotriazinc A mixture of 10 parts ofo-methoxybenzoguanamide, prepared as in Example 3, 21 parts phosphoruspentachloride, and 46 parts phosphorus oxychloride, is refluxed untilchlorination is complete. The product is then drowned rapidly in about800 parts of a mixture of ice and water. stirred vigorously, filtered,washed and dried. It may be purified by dissolving in benzene,filtering, and evaporating to dryness. It melts approximately at 136 C.

EXAMPLE 5 2- (1 -hydroryphenyl) -4,6-dichlorotriazine A mixture of 18.9parts of o-methoxyphenyl dichlorotriazine and 160 parts ofo-dichlorobenzene is heated to 150 C. and treated with a stream ofanhydrous hydrogen bromide until dealkylation is complete. The hydrogenbromide is then replaced by a stream of anhydrous hydrogen chloride atthe same temperature until replacement of bromine by chlorine iscomplete. The solvent is removed by distillation in vacuo and the crudeproduct recrystallized from methylcyclohexane. It melts at approximately155 C.

EXAlVIPLE 6 120 parts of 2-(2'-hydroxypheny1)4,6-dichloro-1,3,5triazineis dissolved in 4,000 parts or" carbon tetrachloride. Five parts of ironpowder is added and at 30 a slow stream of chlorine is passed throughthe mass. After several hours, the temperature is raised to 50 and theintroduction of chlorine is continued at this temperature until twochlorine atomshave been introduced. The solvent is removed bydistillation and the crude chlorinated product is recrystallized from1,900 parts of methylcyclohexane. Pale yellow needle-like crystals wereobtained.

If instead of chlorine an excess of bromine is added in the aboveexperiment, the corresponding 2-(3,5-dibromo-2e-hydroxyphenyll-iifi-dichloro-1,3,5-triazine can be prepared.

EXAMPLE 7 2- (o-hydrowyphenyl) -4,6-dibromotriazine A solution of 1255parts of o-methoxyphenyl dichlorotriazine in 65 parts ofo-dichlorobenzene is heated to 150 C. and treated at this temperaturewith a stream of dry "hydrogen bromide gas until demethylation iscomplete. The mixture is then cooled and filtered, the product beingwashed with hexahydrotoluene. An excellent yield is'obtained. Ifdesired, the product can be purified by recrystallization .from carbontetrachloride or benzene.

EXAMPLE 8 o1 Cl EXAMPLE 9 The procedure of Example 8 is followed,substituting 8.1 parts of bromine for the sulfuryl chloride. Thetetrabromohydroxyphenyl triazine is a yellow solid.

EXAMPLE 10 01- I Cl 'OQH:

25.6 parts of 2-(o-methoxyphenyl)-4,6-dichloro-1,3,5-triazine isintroduced into 130 parts of dichlorobenzene and 0.4 part of iodine areadded. 42 parts of sulfuryl chloride is gradually added 6 at :roomtemperature. The rmass ."heated nto C. randststirredat ithisvtemperatureuntil two chlorine atoms'z-have been introduced. After removing excesssulfuryl chloride under reduced pressure, the reactionmixtureis cooledto 5-10. Theprecipitated crystals are removed byfiltration and washedwith methylcyclohexane. After recrystallization from methylcyclohexane,pale yellow needle-like crystals of the dichloromethoxyphenyldichloro'triazine are obtained in excellent yield.

7.5 parts of 2-(3,5-dichloro-2'-methoxyphenyl)-4,6-dichloro-1,3,5striazine are introduced into 39 parts ofdichloro-benzene and the mass is heated to C. Anhydrous hydrogen bromideis passed through the solution for some time. The mass is cooled to 15C. and the reaction product is separated "by filtration, washed anddried. In it can be found 2-(3',5'-dichloro-2'- hydroxyphenyl)-'4,6-dibromo-1;3,5-triazine.

EXAMPLE 12 'Z-methowy-5-chlorobenzoyldicyandiamide .28 parts ofJ2-methoxye5-chlorobenzoic acid is converted .to acid chloride in theordinary way by treatment with thionyl chloride, the reaction beingcompleted .by gradual heating followedby removal of excess thionylchloride under reduced pressure. The resulting product is dissolved inv40-parts of acetone.

A mixture of 23.4 parts of 'dicyandiamide, 136 parts of acetone and 1.5parts of Water is cooled to 0 C., treated with 19.6 parts (pure basis)of flake potassium hydroxide, stirred thoroughly at approximately 0 0.,and slowly treated with the above prepared acetone solution of2-methoxy-5- chlorobenzoyl chloride. The resulting slurry is drowned inice water and made weaklyacidic with dilute -sulfuric acid. The-productis then filtered and washed "free of acid. A good yield is obtained. Itmelts at approximately 220 C. with decomposition.

EXAMPLE 13 Z-methoxy-5-chlorobenzoylbiuret A solution of 3 parts of 99%sulfuric acid in '70 parts of water is added to 5.0 parts of the aboveprepared 2-methoxy-5-chlorobenzoyldicyandiamide, which is first wettedwith 12 parts of ethanol. The mixture is then refluxed until thereaction is complete, the alcohol being allowed to distill out. Theproduct is cooled, filtered, and dried at 60 .C. A good yield isobtained of product meltingapproximately 198 C. with decomposition.

EXAMPLE 14 Z-methomy-5-chlorobenzoguanamide A mixture of 4.4 parts ofthe above prepared 2-methoxy-5-chlorobenzoylbiuret, 2.5 parts of sodiumhydroxide, and 50 parts of water is stirred until ring closure takesplace and allowed to stand overnight. The solution is filtered andweakly acidified with 20 B. hydrochloric acid.

7 The resulting slurry is cooled in an ice water bath and filtered. Agood yield is obtained. The product melts approximately at 250 C. withdecomposition.

EXAMPLE 15 2-methoxy-5-chlorophenyl dz'chlorotriazz'ne A mixture of 3.3parts of the above prepared 2-methoxy-5-chlorobenzoguanamide, 6.3 partsof phosphorus pentachloride, and 17 parts of phosphorus oxychloride isrefluxed until chlorination is completed, drowned in about 250 parts ofice and water, and stirred for 1 hour. The product is filtered, washed,and dried at 60 C. If desired, it can be purified by extraction withbenzene followed by evaporation. It melts at approximately 156 C.

EXAMPLE 16 2-hydroxy-5-chlorophenyl dibromotriazine N N Brr m N a i N inwhich Ar is an o-phenylene radical and X is selected from the groupconsisting of chlorine and bromine.

2. A compound of the formula Br Br 3. A compound of the formula 4. Acompound of the formula N N Br- NJBr 5. A compound of the formula 6. Acompound of the formula N Br-k Br N 7. A compound of the formula Br- BrN N Bri Br N 8. A compound of the formula BriN -Br 9. A process ofpreparing a compound according to claim 1 by deealkylating a2-o-alkoxyaryl-4,6-dihalotriazine compound of the formula ilk-0A1];

in which Alk represents a lower alkyl radical, Ar represents ano-phenylene radical, and X represents halogen, by treatment with ahydrogen halide in an inert organic solvent at a temperature between C.and 200 C.

No references cited.

1. THE NEW 2-O-HYDROXYARYL-4,6-DIHALOTRIAZINE COMPOUNDS HAVING THEFORMULA